Refrigerators and Freezers employ gasketed doors to provide an insulated chamber without significant leakage and energy loss. However, in some appliances such as newer freezers the appliance is so tight and the gasket so effective that users have trouble opening the door, particularly after it was recently shut.
When door of an upright freezer kept at 0 degrees Fahrenheit is opened, the cold air flows downwardly outward from the chamber, while the contents remain cold. What the door is closed a short time later, the cold air has been replaced by much warmer ambient air. This newly-trapped warm air is rapidly chilled by contact with the frozen contents and structure, and naturally contracts. This creates a substantial pressure differential that effectively sucks the door closed. For a large freezer with a door 3 feet wide and six feet tall, the surface area is 2592 square inches. A pressure differential of only 0.04 PSI is enough to initially create a total force of more than 100 pounds on the door, making it effectively impossible to open. At this level of suction, the door and handle may be damaged by determined efforts to open the freezer.
Because the gasketing is imperfect, the pressure will eventually equalize as ambient air leaks into the chamber. However, this pressure relief is often frustratingly slow, such as when a user lets the door close just before remembering to get something else from the freezer. This “time lock” effect generates a need for a facility to relieve the pressure differential at a reasonable and selectable rate without introducing unjustifiable energy waste and or irreversible disadvantages.
The preferred embodiment addresses these and other needs by providing a pressure relief facility for a refrigeration appliance with a body defining a chamber and having a peripheral rim, the appliance having a door with a peripheral gasket operable between an open position in which the gasket is away from the rim and a closed position in which the gasket sealably contacts the rim. The relief facility includes a planar body having opposed major faces and having opposed first and second peripheral edges. The body has a number of passages adjacent to each other, each passage having a first opening at the first peripheral edge, and a second opening at the second peripheral edge. An adhesive element is attached on one of the major faces adapted to secure the body to the rim of the appliance body in registration with to the gasket with the first openings in communication with the chamber, and the second openings in communication with ambient air. The planar body may be an elongated rectangular piece of corrugated plastic, with the passages running transverse to the length.